Grade-crossing signal



c.`w. DUNHAM.

GRADE CROSSING SIGNAL.

APPLICATION HLED APR.24.1911

1,330,064. Patented Feb.10,1920.

3 sHEEls-SHEU 1.

i i. I g

C. Wl DUNHAM.

GRADE CROSSING SIGNAL.

I APPLICATION FILED APII.24. 19H.

1,330,064. Patented Feb. 10,1920.

3 SHEETS-SHEET 2.

WITNESSES INVENTOR ww www WM.

C. W. DUNHANI.

GRADE CROSSING SIGNAL.

APPLICATION FILED APL-24. y1911.

Patented Feb. 10, 1920.

3 SHEETS-SHEET 3- WITNFSSESS I l I I. INVENronf/pVt I Ja. citizen of the United States, residin Edgewood Borough, in the county of lle- UNITED sTATEs PATENT oEEIoE.

CHARLES W. DUNHAM, or EDGEWooD BOROUGH, PENNSYLVANIA, ASSIGNoE To THE UNION SWITCH & SIGNAL coMrANY, 0F sWISsVALE, PENNSYLVANIA, A. coEroEA- TION 0F PENNSYLVANIA.

GRADE-CROSSING SIGNAL. l

Application led April 24, 1917. Serial N0.l164,111.,

T0 all whom t may concern:

Be it known thatv I, CHARLES W. D UNfHAM,

ghelly and State of Pennsylvania, have invented certain new and useful Improvements in Grade-Crossin `Signals, of which the following is a speci cation.

My invention relates to warning signals for intersections of highways and railways.

I willdescribe one form of signal and one controlling means for such signal, each embodying my invention, and will then point out the novel features thereof'in claims.

In the accompanying drawings, Figure 1 'a view showing in front elevation the actuating mechanism for the signal shown in Fig. 1, the mechanism being removed .from

the casing C and partly shown in` section. Fig. 3 is a view showing in side elevation the mec anism shown in Fig 2. Fig. 4; is

a diagramm'atical view showing one form-A `of controlling apparatus embodying my :in-

vention.

Similar reference characters refer to Similar parts in each of the views. v Referring to the 'drawings in detail and particularly to Fig. 1, I have vhere shown a Vwarning signal S embodying .my Invention, which signal is located adjacent the intersection of a railway T and al highway H. The Signal comprises, in this instance, a post or standard 9 lupon the upper end of which is mounted a casing C containing the operatingl mechanismlfor a semaphore D. The

semaphore D is ofthependulum type, that is, a.semaphore\which vis caused to oscillate to give a danger-indication, thereby warning persons crossing the railway track of an ap'- The selnaphore as here shown comprises a rod 10 and a(bob 11, the bob consisting of a disk 12 colored preferably red and having imprinted upon the opposite sides thereof the word Stop. e

As shown in Fig.' 1, the semaphore is pivotally mounted at point 10a upon the outer end' of a tubular arm 14 secured to 'casing C, the arm being supported in horilatched.

.nism through the medium of a connecting specification/of Letters Page Patented Feb. 10,' 1920.

in Fig. 1, in which position the shields 17' conceal the disk l2. Y For the purpose of givin a danger indication at night, the disk l1 o the semaphore is provided with an electric lamp 13. This lamp, as hereinafter t explained, is so -controlled that it is il1uminated only when-the semaphore is n- I will now' describe the mechanism for within the casing C and comprising .front 'oscillating theI semaphore D, reference being and reai sections f and f respectively,- spaced apart by means of-bolts, as shown. The

rear .side of the rearsection f is formed with f a horizontal shelf 18 uponwhich are mounted two electromagnets m and m. lThese magnets are disposed at opposite sides of a horizontal shaft 19, the latter being jourf f naled in suitable bearings formed in the frame F. The upper ends of the electromagnets are formed with pole pieces 20 and 20, while loosely mounted on, the Shaft '19 and arranged upon opposite-Sides'thereof are armatures 21 and 21a, which are adapted to ybe operated by their corresponding, electroarmatures 21 and 21a downwardly, and during such movement the armatures are causedv to alternately engage thearms 22 and 22a, whereby oscillatory motion is transmitted to the shaft 19. By virtue of this oscillatory movement of the shaft 19, an operating crank 23 fixed to the shaft between the sections f and f ofthe frame F is caused to oscillate, which'in turn swings the semaphore D to and fro through the medium of the connecting rod 16. A weight' 24 is fixed to the shaft 19 between the sections of the Vframe F for the purpose of balancing the crank 23, as will be understood.

iVith the parts of the mechanism proportioned as shown in Figs. 2 and 3, when the.4

semaphore is vin the vertical position each armature 21, 21a is spaced about 5o fro-m the pole pieces of the corresponding magnet, `and .each armature is resting on its' correspond- A nets m and' m to cause oscillatory movement yof the semaphore D, as just described. Re-

ferring to Figs. 2, 3 and 4, the circuit controller is indicated generally at K, and as here shown, comprises a terminal board 25 secured to the end of the frame F' andv upon which are mounted a. spring contact finger 26 and two spring contacts 27 and p27, the spring contact linger being interposed between the spring contacts and iased'by means of its own tension to normally engage the Contact 27. Pivoted on the frame F at 28 is an arm 29, the upper e-nd of which carries a block 30, formed of insulating material, which is provided with a slot 31 to receive the lower end of the contact 'finger 26. Y.The lower end of arm 29 is bifurcated andcarries a pin 29aL on' which i two rollers 32 and 321l are free .to revolve. The outer end of the shaft 19 is provided with a sector cam 33 fixed to the shaft for movement therewith, the curved edge of' which is formed with four cam surfaces a, b, cand a', such surfacesl being adapted to successively engage the roller 32 when the cam is oscillated'.` It will be noted that the cam surfaces',a, and c-areeach disposed at a different radius, taking the shaft 19 as a center, and that the iadius of surfacea is.

the saine as that of surface a. 34 designates a pivoted cam, the free end o f which is disposed at substantially thev same radius as the cam surface c. The cani 34 is .biased in a -clockwise,direction by means of springs and 35a carried -bycam 33, the upward move- 1^ ment of the'cain being limited by a stop 36 ateswith roller 32%y y 1,As previously stated, the semaphore D is carried by the cam 33. 7This lcani 34 coperadapted to be latched in an inclined position b v means of alatching device, which I will noiw'describe. Referring to Figs. 2 and 3, the latching device is designated generally an armature 42 mountedon an arm 43, the

latter having its lower end bifurcated and pivotally mounted'on a pin 44. The armature 42 is biased toward the pole pieces of the magnet M2 by means of a counterweight 45a fulcrumed upon the .pin 44 in the bifurcation at the end of the arm. This counterweight is carried on a. bent lever 45, the portion of which above the pivotal'point 44 rests against a projection 43b on the arm 43. The armature 42 is not, however, biased into actual contact with the poles of the magnet M2 but to a position slightly spaced from the poles. This is due to the fact that the clockwise movement of the lever 45 is limited by means of a stop screw 45" carried by the lever and passing through a slot 43a in arm 43. When this screw is properly adjusted the leveirwill move the armature to the previously mentioned spaced position and no farther, as the screw 45b will then engage the frame of the magnet as shown in Fig. 2.

The reason for thus biasing the arm-ature to a position-in spaced relation to the polepieces of the magnet will appear hereinafter.

Pivotally connected to the medial portion of the arma-ture 42 by a pin 46a are apair of spaced links 46, 46, the upper ends of which carry a pin 70. Pivotally mounted on this pin aretwo other spaced links 71, 71a, the other ends of which are pivoted ona pin 48v which is mounted in frame F. Also pivotasllymounted on the pin 70 is'a locking dog 47, the free end of which is forked to straddle the fixed pin 48. The upper `arm ofthe forked end of the dog 47 is beveled Ato provide a tooth 49, which whenthe dog is elevated to the position shown, is adapted t'o engage arack bar 50 carried by the operating crank 23. The dog 47 is elevated by the armature 4 2 when the latter is attracted by the magnetMZ,

through'the medium of a leaf spring 51 which is pivotedly mounted upon the armature A42 by means of a bracket 52. A yoke53 and a pin 54 confine thes-pring v51 between the links 46, 4.6, suclr spring having its upper end engaging a 'lug 55 formed on the dog'47. A screw- 56 adjustably mounted onthe Aarinature 42 is'arranged for engagement with the spring 5lwhen the armature is in attracted position, but not when the armature .is released.

The operation. of the .latching device is as follows.: When magnet M? is energized,

armature 42 is closed againstthe pole pieces of this magnet so that screw 56 presses against the leaf spring v51. The upper end of this spring then presses. against the lug 55 von dog 47, rso that this dog` is swung upwardly to such position'4 that its tooth 49 engages one of the teeth on rack bar 507 thereby latching the semaphore in its eX- treme 'left hand position against the -action' of gravity on the semaphore. This is the leased and will swing out, thus allowing the links 46 to swing outwardly and downwardly under the influence of the force eX-I' erted on dog 47 by rack.bar 50. The dog will then swing down around tooth 49 as a center until this tooth is out of the path of rack bar 50,A but the forked Kend of the dog will be kept astraddle of pin 48 owing to links 71, 71a. rlhe semaphore is then free to swing under the influence of gravity and of magnets m and m.' As soon as the semaphore is thus released, however, counterweight a will return the armature 42 to nearly its closed position, so ,that dog 47 will be.returned nearly to itsv latching` position. Screw 56 does4 not eXert any `pressure on spring 51 at such time, however, hence the dog will rest with the upper arm of its forked end lying on pin 48, and in this position the tooth on the dog will be just out of the pathof the teeth on rack bar 50. If, then, magnet M? becomes energized, the closing of armature 42 will cause screw 56 to exert pressure on spring 51, and the upper end'of this spring will then swing dog 47 upwardly so that its tooth 49 will engage with one of the teeth on rackA bar 50 the neXt time the semaphore swings to its eX- treme left-hand position. The semaphore will consequently'be caught and held in this position. f

It' will thus be seen that when the magnet M2 is denergized, armature42 is heldy in nearly its closed `1position and the dog is held in nearlyits latching position7 so that only a small amount of pull on'the armature is required to move the parts into active or latching position. This construction, therefore, makes it possible to use a small controlling magnet and a comparatively lsmall amount of current to energize the magnet.

The operation of the signal` will be described in connection with the controlling means for such signal shown' in Fig. 4. Re'- fer-ringto Fig. 4, I have here shown diagrammatically the signal S, one arrangement of circuits therefor, and one means for automatically controlling such circuits. T

designates a stretch of railway track as in.

Fig. 1. The rails of the stretch are divided to form a track section by means of insulated joints 57, 57. Although I have shown only one of such sections, it is to be understood-that a pluralitybfsections may be employed for rcontrolling the signal S by "m-eans 'of interlocking relays, as 'will be. understood b v those Aversed in the art; Thev track section here shown is provided with .a

`tery`B through an upper contact 41, contact track circuit including a battery B con-v nected across the track rails at one end. of thev section and a relay R- bridging the track rails at the other end of such section. Relay R is provided with two contact fingers 58 and 59, respectively. Contact linger 58 controls the supply of ,current to the lamp 13 from a battery B ,through a lower con# tact 58a, while contact finger 59 controls the supply of current to magnet M2' from bat- 593. From this arrangement it will be seen that when the relay is energized contact linger 58 disrupts the lamp circuit, while contact linger 59 completes the circuit for the magnet M2. When the relay is denergized the reverse operation of the contact fingers occurs to complete the lam-p circuit and to disrupt the circuit for the magnet M2, as will be understood. The circuits Jfor the lamp 13 and the magnet M2 are thought to be obvious, and thereforethe same will not be traced.

As shown in Fig.4, magnets m and m are I supplied with current from a battery B, the circuit for magnet m being from battery B, through wires 60, 40 and 39, windings of magnet m, wire 38, contact27, contact finger 26, and common return wire 37 back to battery. he Acircuit for magnet m is from battery B, wires 40 and 39, magnet m, wire 27-26, back lto battery. Although the lamp 13 and the magnet M2 are supplied with current from the same source as the magnets m and m, it will be noted that the magnets m and m are controlled independently of the relay R and its con tact fingers.

The operation of the signal is as follows:

AWith the parts in the normal positions, as

shown in Fig. 4, let it be assumed that a trainor car enters the track section. Relay R lis, immediately denergized torelease the latching device L and illuminate the lam 13.

.With the latching device released, the semaphore D starts to swing from its latehed position, which movement lcauses cam 33 to be moved ina clockwise direction, Soon after this'movement begins, cam surlface b moves to such position that itis opposite roller 32, and inasmuch as contact linger 26 is biased to closel against contact 27, arm 29 then swingsin counter-clockwise direction so that .contact 26427 closes. Magnet m then becomes energized to attract its armature and so to transmit a force to crank 23 which force assists the action of gravity tending to swing semaphore D to the right. As the movement continues, cam 34 is engaged by roller 32a and caused to swing with relation to cam- 33, in opposition to the action of springs 35 and 35. After the entire surface. has traversed roller. 32, this roller rides outwardly on in- `lclined surface b until roller 32a reaches the upper corner 3'4a of cam 34. At this point .the action of springs 35, 35a overbalances occurs, semaphore D is 5o beyond the verti cal position so that armature 21 has just reached pole pieces 20. Magnet 'm then becomes denergized and magnet m becomes energized, but this does not materially retard the movement of the semaphore because armature 2la is then 10Q away from the poles of its magnet and so is practically out of the iniuence of this magnet. Furthermore, the impedance of the coils prevents the magnetic field from reaching a high value during the brief interval in which this magnet is energized. As soon as the snap action just `referred to has taken place,

A cam 34 returns to its initial position under the influence of springs 35, 35a, but this does not affect the position of arm 29. No change occurs when roller 32a leaves cam 34 and. roller 32 rides onto surface c, because the radius of surface 0 and the radius of surface 34b are the same. As the movement of the semaphore continues, roller 32 rides down onto cam surface af, whereupon arm 29 swings enough to allow contact linger 26 to return to its middle or open position, thus denergizing magnet m. Soon after thislast movement of roller 32 takes place, the semaphore reaches its extreme righthand position and starts to return under the influence of gravity, whereupon cam 33 moves in cunter-clockwise direction. l.After contact 26--27a. energized to assist the action of gravity in swinging the semaphore. After surface c oleaves roller 32, cam 34 coperates with roller 32a to hold contact 26--27a closed, that is, to keep-magnet m energized, until the semaphore is 5o beyond its middle position, when cam 34 suddenly releases roller 32a and so allows roller 32 to drop to cam surface b. Magnet m then becomesenergized for a short time, but is thereafter denergized when roller 32 reaches cam surface a whereupon the contact finger 26 is returned to its middle or open position.

It will be seen from the foregoing that during each swing of the semaphore the magnet which assists insuch swing becomes denergized when the semaphore reaches a point 5 beyond its vertical position.' The object of this is to use as little energy as possible by taking advantage of the pendulum principle and obtaining a compara'- tively large amplitude of swing by the cumulative effect of impulseswhich -individuv ally would not be able to produce such an amplitude. It will be further seen that the reversal of contact finger 26 is always accomplished by a snap action due to thel operation of roller 32a by cam 34. This action avoids the possibility of' thev semaphore being in such position as to be deprived of motive power, as might occur when the arc of oscillation is very small if the reversal of the contact finger took place slowly.

It will be evident, therefore, that with the latching device released, the semaphore D is swung to and fro continuously, so long as a train remains within the track section, and that such movement of the semaphore gives a warning indication to persons approaching the grade crossing. When the car or train passes out of the track section,l the' relay R is again energized to extinguish the lamp and to'cause the latching device to assume its active position. Then asthe semaphore in its swinging movement reaches its extreme position between the` shields 17, the latching deviceengages the crank 23 and thereby locks the semaphore in obscured position, so that the signal again givesa clear or safety indication.

It will be clear that in the event of failure of battery B, the semaphore will be released, and will hang idly in the vertical position, thus indicating lthat the signal is out of order. Should, however, the latching device become yineEective while theoperating magnets remain effective, the semaphore will be released and continuously oscillate, thus giving the warning or stop indication. d

It is to be understood that the track section to which relay RV is connected is located adjacent the grade crossing so that the signal S will be operated before` the tram or car reaches such crossing. l

Although I have herein shown only one form of signal and one-controlling means, each embodying myv invention, it is understood that various changes and modifications may be made therein within the scope of the apppended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A highway crossing signal comprising a semaphore, means for continuously moving said semaphore, latching means for locking said semaphore against'movement, a c1r- 12| cuit controller operated by said semaphore for controlling said moving means, said circuit controller being capable of assuming two extreme positions to actuate said moving means and an intermediate position to 128 render said moving-means inactive, said circuit controller maintaining the intermediate position when the vsemaphore is in locked pos1t1on.

2. A highway crossing signal comprising 130 a semaphore, means for continuously moving said semaphore and comprising a pair of electromagnets, means for latching said semaphore in a .predetermined position,

. means for controlling said magnets comprising'a contact finger and a cam operable by said semaphore for actuating said finger to released and comprising two electromagnets,

a contact finger, a cani actuated by ysaidI pendulum to move said contact finger to alternately energize said electroniagnets to continuously move said pendulum and to deenergize said electromagnets when the pendulum is in latched position, and an electroresponsive device controlling said latchi'ng means.

4. A highway crossing signal comprising a pendulum semaphore, means for continuouslykswinging said semaphore, and a latching device for said semaphore, said latching device comprising a member moving with the semaphore, an electromagnet, a dog engageable with said member, and means operable by said electroniagnet for moving said dog into and out of engagement with said member, said means comprising an armature biased yto a position slightly spaced from the poles of said electromagnet but capable of liberal movement away from said magnet to permit disengagement of said dog from said member.

5. A highway crossing signal comprising a pendul-uni semaphore, means forcontinuously swinging said semaphore, and a latching device for latching said semaphore in one of' its extreme positions, said device comprising an oscillating member biased to a point adjacent one end of its stroke, a dog operable by said member, means for moving said member to the end of its stroke, and resilient mea-iis'connecting the dog and member for moving said dog into engagement with said semaphore when said member is moved'to the end of its stroke. v

6. highway crossing signal comprising a pendulum semaphore, means for continuously swinging said semaphore, and a latching deviee for latching said semaphore in one of its extreme positions, said device comprising a. member moving with the semaphore, an electromagnet, a pivoted armature for the electroniagnet biased -to a point ad- ,jacent the poles of said electromagnet, a

dog, and means connecting .said dog and armature for moving the dog into engagement with said membel` when said electromagnet is energized.

7. A highway crossing signalA comprising a pendulum semaphore, means for continuously swinging said semaphore, and a latching device for latching said semaphore in one of its extreme positions, said device comprising a member moving with the seniaphore, an electromagnet, a y-pivoted armature for the electroniagnet biased to a point adjacent the poles of said electromagnet, a dog, and adjustable resilient means connecting vsaid dog and armature for moving the 'dog into engagement with said member when said electromagnet is energized.

8. A highway crossing signal comprising a pendulum semaphore, means for continuously swinging said semaphore, and a latching device for said semaphore comprising a dog, a pivoted member biased to an intermediate position,'and means for moving said member to another position to cause said dog to latch said semaphore, said mem-ber being capable of assuming still another position wherein said dog releases the semaphore.

9. A ai pendulum semaphore, said semaphore in an inclined position, means comprising a member moving with the semaphore, a dog, an electro-responsive device, mechanism operatively connecting said dog and electro-responsive device for moving said dog v.into engagement with said member, when said electro-responsive device is energized, the engagement of said dog and said member being such as to allow said dog to be forced outv of engagement with said member when the electro-responsive device is denergized; and biasing means for ieturning said do=gto nearly its engaging position.

10. A latching' devic-efor a pendulum semaphore signal, comprising a member moving with the semaphore, a dog, an electromagnet, an armature for said magnet,

means for latchiiig means interposed between'said armature-ani said dog for holding said dog 1n engagement with said member to latch the semaphore when the armature is attracted by said magnet and for permitting said dog to move out of the path of said member when the armature moves a considerable distance from the poles of the magnet, and means for biasing said armature to such position that it is nearly closed against the poles of the magnet, in which position the dog is nearly but not quite in position to engage said member.

11. A latching device for a pendulum semaphore signal, comprising a rack bar 50 movable with the semaphore, an electromagiiet M2, an armature 42 for said magnet pivotally mounted at 44, links 46 pivotally attached to said armature, links'7l, "('1a pivotally connected with said links 46 by a pin 7 0,

a fiXed pin 48 to which links 71, 71a are p'rvhighway crossing signal comprisingsaid l on pin and having a tooth 49 adapted to engage the teeth of rack bar 50, said dog having a pait adapted to' rest on pin. 48, whereby when the arn'iature swings away from the magnetpoles, the dog may swing to such position that its tooth 19 is out of the path of rack bar 50, a. counterweight 45a for biasing yarmature 42 to nearlyits closedposition wherein the upper arm of the bifurcated end of dog 17 rests on pin i8' and. tooth 19 is out of the path of rack bar 50, a leaf spring 51 pivotally attac-hed to armature 42 and cooperating with a lug 55 on dog i7, and a member 56 attached to the armature for exerting pressure on the leaf spring when the armature is closed and for thereby swinging dog 47 into the path of rack bar 50.

12. A signal comprising a pendulum sem2 aphore, twoelectroinagnets for swinging said semaphore in opposite directions, a circuit controller for governing said magnets comprising a contact finger capa-ble of a middle position in which both magnets are denergized and two extreme positions in which one magnet or the other is energized, and means controlled by the semaphore ,for swinging said contact finger to one extreme position or the other while the semaphore is approaching its 'middle position from one direction or the other and for holding the contact finger in its middle position while the semaphore is in an extreme position.

13. A signal `comprising a pendulum semaphore, a magnet mfor swinging` said semaphoretoward the right and a magnet 111. for swingino said semaphore toward the left. means for latching said semaphore in one extreme position of its stroke, means including a contact finger 26 for energizing one magnet or the other according as the finger is moved to one extreme position or the other; and means controlled by said semaphore for moving Isaid finger to eneigize magnet m whilethe semaphore is approaching its middle position from the left, for moving said finger to energize magnet m. while the semaphore is approaching -its middle position from the right, and for holding said'fiiiger in an intermediate position wherein both magnets are denergizedl while tion.

14. A signal comprising apenduliini semaphore, a magnet m for swinging'said semaphore toward the right and a magnet m for swinging said semaphore toward the left, inea-iis for latoliing said semaphore kin one extreme position of its stroke, means including a contact finger 26 for energizing magthe semaphore is in said extreme posinet .m or magnet m according as such finger engages a fixed contact 27 or 27a and for deenergizing both magnets when such finger is out of engagement with both of said congagement with either contact while the semaphore is in said extreme position.

15. Asignalcomprising a pendulum semaphore, two magnets m and m for swinging l said semaphore yto the right and left resi-pec- `tively,v means including a contact finger 26 y for energizing magnet m or m according as suc-h finger is moved into engagement:v

with a. fixed contact 27 `or 27a, a cam 33 moving with the semaphore and having four cam surfaces a, I), c, and a; a cam follower co `iperating with said surfaces for permitting said finger to move into engagementwith contact 27 while the follower rests on surface Z), for shifting said finger into engagement with contact 27a when the follower rests on surface c, and for holdingsaid finger out of engagement with both contacts when the follower rests on surface a; or a; said cam surfaces being so arranged that thekfollower rests on surface a o r atV while the semaphore is inone extreme position or the` other and that surface Z) is opposite the follower while the semaphore is approaching` its middle position,and a second cam ment with contact 27a while the semaphore is approaching its middle position from the right. l i

16. A signal comprisinga pendulum semaphore, two magnets ym and m" for swinging said semaphore to the right and left respectively, means including a contact finger 26 for energizing magnet lm or m according as such finger is moved into engagement with a fixed contact 27 or 27, a ca m 33 moving with the semaphore and having two cam surfaces and c, a. ,cam follower coi'iperating with said surfaces for permitting said finger to engage contact 27 when the follower rests on surface and for shifting the finger into engagement vwith contact 27'EL when the follow-er rests on surface c, said cam sur-A faces being so arranged that lsurface is opposite the follower while the semaphore is approaching its middle position, and a sec'- ond cam 31 for holding finger 26 i'n engagement with contact 27a while the semaphore is approaching its middle Apositionfrom the right and iin-til the semaphore has passed beyond such middle position.

In testimony whereof I afiix my signature in presence of two witnesses. Y

CHARLES W. DUNHAM.

Witnesses R. HERMAN WEGNER, FAY GLASGOW. 

